Physiology

Question 1

What is creatinine?

Answer 1

A product of muscle metabolism.

Will be higher in those with high muscle mass.

Question 2

How do creatinine levels change in those with a low GFR?

Answer 2

High creatinine

Question 3

Which eGFR level is described as stage 5 CKD?

Answer 3

<15ml/min

Requires dialysis/renal transplant.

Question 4

Which eGFR level is described as stage 4 CKD?

Answer 4

15-29ml/min

Requires treatment to preserve function.

Question 5

Which eGFR level is described as stage 3 CKD?

Answer 5

30-59ml/min

Often seen in elderly patients - normal decline in renal function seen in age.

Question 6

Which eGFR level is described as stage 2 CKD?

Answer 6

60-90ml/min

Question 7

Which eGFR level is described as stage 1 CKD?

Answer 7

> 90ml/min

Question 8

How much protein content is needed to be pathological in urine?

Answer 8

150mg/day

Question 9

Which group of conditions cause gross oedema and significant proteinuria?

Answer 9

Nephrotic syndrome

Question 10

How does protein loss lead to oedema?

Answer 10

Proteins should act to drag water out of the tissues and into the blood vessels.

When lost, results in leakage into tissues - producing oedema (nephrotic syndrome).

Question 11

What may microalbuminuria indicate?

Answer 11

Diabetic neuropathy

Question 12

What should be given to prevent worsening of diabetic nephropathy?

Answer 12

ACE inhibitor

Question 13

Does high osmolarity mean high concentration?

Answer 13

Yes, high osmolarity means high ratio of solute compared to water molecules.

Question 14

Should plasma osmolarity be higher than urine osmolarity?

Answer 14

No, urine osmolarity should be higher.

Question 15

Which hormones are produced by the kidneys?

Answer 15

Renin (regulates BP)
Erythropoietin (encourages RBC production)

Question 16

Which hormone controls the reabsorption Na+ in the distal convoluted tubule?

Answer 16

Aldosterone

Results in greater Na+, increasing blood volume (and therefore pressure).

Question 17

What is the effect of a hypotonic solution?

Answer 17

Increases cell volume

Question 18

What is the effect of a hypertonic solution?

Answer 18

Decreases cell volume

Question 19

In which compartment is the majority of water found?

Answer 19

Intracellular - makes up 67%.

Question 20

What 4 components make up the total extracellular fluid compartment?

Answer 20

Plasma
Interstitial fluid
Lymph
Transcellular fluid

Question 21

Which ions are most concentrated within the ECF?

Answer 21

Sodium
Chloride
Bicarbonate

Question 22

Which 2 ions are most concentrated with the ICF?

Answer 22

Potassium
Magnesium

Question 23

What is responsible for the movement of fluid between the ICF and ECF?

Answer 23

An osmotic gradient

Question 24

What is the typical kidney output of urine per day?

Answer 24

1.5L/day

Question 25

How is bilirubin produced?

Answer 25

It is a by-product of haemoglobin metabolism.

Question 26

How is uric acid produced?

Answer 26

A by-product of purine metabolism.

Question 27

What is the role of erythropoietin?

Answer 27

To stimulate RBC production.

Question 28

How does the kidneys process vitamin D?

Answer 28

Converts this to calcitriol (active form).

Question 29

Can the bladder/ureters alter the composition of urine?

Answer 29

No, last alterations to this are at the kidneys.

Question 30

Which 3 mechanisms take place at the nephrons to create urine?

Answer 30

Filtration Reabsorption Secretion

Question 31

How does blood pass through the kidneys?

Answer 31

Renal artery > Afferent arteriole > Glomerulus > Efferent arteriole > Peritubular capillaries > Venules > Renal vein > IVC

Question 32

What is a normal GFR?

Answer 32

120ml/min

Question 33

What is the first step of urine production?

Answer 33

The passage of some plasma across the Bowman's capsule, becoming the tubular fluid.

Question 34

What 3 barriers act to limit the glomerular function?

Answer 34

Glomerular capillary endothelium (blocks passage of RBCs) Basement membrane (albeit has pores) Slit processes of podocytes

Question 35

What is the purpose of podocytes?

Answer 35

To act as a molecular sieve - only small molecules can pass through.

Question 36

What is GFR?

Answer 36

The rate at which protein-free plasma is filtered from the glomeruli into the Bowman's capsule, per unit of time.

Question 37

What is the purpose of the extrinsic regulation of the GFR?

Answer 37

When blood volume drops, afferent arterioles constrict, reducing urine production. Ensures minimal fluid loss. Regulated by sympathetic nervous system.

Question 38

What is meant by the term autoregulation?

Answer 38

The intrinsic regulation of kidney function by the kidney itself.

Question 39

Which cells produce constriction of the afferent arteriole in order to lower GFR?

Answer 39

Macula densa

Question 40

Clearance of which molecule is viewed as 'gold-standard' in determining GFR?

Answer 40

Inulin

Question 41

What is creatinine?

Answer 41

An endogenous substance produced during skeletal muscle metabolism. Released at a constant rate.

Question 42

Initially, what differs between tubular fluid and plasma?

Answer 42

Not too much, only large plasma proteins are lost. Exclusion due to the negative charge of the basal lamina.

Question 43

Which section of the nephron is reached by the interstitial fluid?

Answer 43

Proximal tubule

Question 44

What is the major site of reabsorption within the nephron?

Answer 44

Proximal tubule

Question 45

What is the only area of the nephron not involved in sodium reabsorption?

Answer 45

Descending limb of the loop of Henle

Question 46

Can water be reabsorbed in the ascending limb of the loop of Henle?

Answer 46

Minimally, primarily responsible for the reabsorption of sodium and chlorine ions.

Question 47

Which form of medication acts on the triple co-transporter of the ascending limb of the loop of Henle?

Answer 47

Loop diuretics

Question 48

How does the triple co-transporter impact the tubular fluid?

Answer 48

Removes solute from the ascending limb - leaving only water behind. Results in dilute urine. Blockage (with loop diuretics) produces concentrated urine.

Question 49

Which limb of the loop of Henle concentrates urine?

Answer 49

Descending

Question 50

Which limb of the loop of Henle dilutes urine?

Answer 50

Ascending

Question 51

What regulates the resorption of water?

Answer 51

ADH

Question 52

What is the action of aldosterone?

Answer 52

Promotes sodium resorption. Allows K+ to be secreted.

Question 53

What is the action of PTH?

Answer 53

Increases calcium resorption Decreases phosphate resorption

Question 54

Which part of the nephron is the ONLY area where hormones can influence the resorption of ions?

Answer 54

Collecting duct

Question 55

What is central diabetes insipidus?

Answer 55

An inability to produce ADH in the posterior pituitary.

Question 56

What is nephrogenic diabetes insipidus?

Answer 56

An inability of the kidneys to respond to ADH within the circulation.

Question 57

How is central DI treated?

Answer 57

ADH replacement

Question 58

How does alcohol impact ADH release?

Answer 58

Reduces it. Explains why need to pee so much when drinking.

Question 59

When is aldosterone released?

Answer 59

Released from the adrenal cortex in response to: High plasma K+ Low plasma Na+

Question 60

Why does aldosterone cause BP to rise?

Answer 60

As resorption of salt is promoted, which causes a rise in blood volume (as water dragged back in), thus increasing BP.

Question 61

How does hyponatraemia affect BP?

Answer 61

Lowers it.

Question 62

Where is renin produced?

Answer 62

Liver

Question 63

Where is ACE enzyme found?

Answer 63

Lungs

Question 64

What are the main functions of angiotensin II?

Answer 64

Promotes aldosterone release Stimulates thirst Promotes ADH release Promotes vasoconstriction

Question 65

What 3 factors can trigger release of renin?

Answer 65

Reduced pressure in the afferent arterioles Macula densa senses the amount of NaCl in the distal tubule Increased sympathetic activity due to reduced BP

Question 66

Which extremes of pH signify a serious risk of death?

Answer 66

<6.8 and >8.0

Question 67

Which enzyme catalyses the creation of H+ and HCO3- ions from CO2 and H20?

Answer 67

Carbonic anhydrase

Question 68

Which organ controls HCO3- levels?

Answer 68

Kidneys

Question 69

Which organ controls PaCO2 levels?

Answer 69

Lungs

Question 70

Can the kidneys create HCO3 when this is low?

Answer 70

Yes, if low levels detected in the tubular fluid, H+ can be secreted into the nephron, binding with phosphate.

Question 71

What is respiratory acidosis?

Answer 71

Retention of CO2 within the body. May be due to lung failure.

Question 72

What is the primary cause of respiratory alkalosis?

Answer 72

Hyperventilation

Question 73

Is metabolic acidosis due to CO2 retention?

Answer 73

No, problem not related to CO2.

Question 74

For respiratory disturbances of acid/base balance, where does compensation occur?

Answer 74

Kidneys

Question 75

For metabolic disturbances of acid/base balance, where does compensation occur?

Answer 75

Lungs

Question 76

Which metabolic acid/base disturbance is most commonly seen?

Answer 76

Metabolic acidosis